1. Field of the Invention
The invention relates to a vehicle control system.
2. Description of the Related Art
The vehicle control system calculates target driving force based on the stroke (i.e., the amount of depression) of the accelerator pedal operated by the driver, and controls a drive system so that the drive system generates the target driving force requested by the driver. However, since the driver changes the manner of operating the accelerator pedal depending on a target acceleration, the driver's request or demand may not be satisfied if the target driving force is calculated only based on the accelerator pedal stroke. Therefore, some known types of vehicle control systems perform driving control, using operation information other than the accelerator pedal stroke.
For example, in a vehicle motion control system as described in Japanese Patent Application Publication No. 2007-247579 (JP-A-2007-247579), the relationship between the accelerator operating speed and the target jerk is set to be variable according to the intention of the driver, and the target jerk is set based on the relationship. Then, a first target acceleration is calculated from the accelerator operating amount; and a second target acceleration that changes relative to the first target acceleration according to the target jerk is calculated, so that driving force is generated based on the second target acceleration. Thus, the second target acceleration is calculated by correcting the first target acceleration calculated from the accelerator operating amount represented by the accelerator pedal stroke, based on the target jerk set based on the relationship with the operating speed of the accelerator pedal; therefore, the target acceleration can be calculated, using operation information other than the accelerator pedal stroke, and the actual acceleration can be made closer to the acceleration requested by the driver.
However, if the target acceleration is corrected using information other than the accelerator pedal stroke, an elevation change or stepped change in the acceleration may occur when the control system returns from a condition where the correction is conducted, to a condition of normal acceleration control, and the driver may feel uncomfortable when such a change occurs in the acceleration.